Hello, I'm one of the senior admins for Hogwarts Golden Age, and one of our members frequently is abusive and aggressive, usually I'd ban the IP, but the user changes it and reports us frequently, what can we do?

Unforantelly all you can do is keep banning his accounts, email addresses and pms. He is probably using a proxy server and the ips arent even real. He will get tired eventually if you keep banning all of the above.

What exactly do you mean by closed? By you guys? By Forumotion? If by Forumotion, dont worry, if you delete his posts and ban his accounts, you'll be fine. Every site gets a troll sometime, all you can do is deal with as best as you can, which you are.